1,720,956 research outputs found
Progressi nei Sensori Biomedicali: Studi Teorici e Sperimentali su Tecnologie Optoelettroniche e Tessili
No full textQuesta tesi si concentra sullo studio e sviluppo di un sensore optoelettronico per il monitoraggio di tossine uremiche, con l’obiettivo di esplorare un modo per ridurre l’ospedalizzazione dei pazienti nell'ottica di sistemi Point of Care (PoC). L’emodialisi, in particolare, è una terapia altamente debilitante per i pazienti, poiché richiede sessioni multiple a settimana in ambiente ospedaliero, ciascuna della durata di diverse ore. Trovare un modo per applicare l’approccio PoC in tali trattamenti sarebbe molto vantaggioso, consentendo ai pazienti di sottoporsi alla dialisi in modo più flessibile e personalizzato, riducendo la necessità di frequenti visite ospedaliere e migliorando la loro qualità di vita.
Le tossine uremiche, tra cui composti legati alle proteine (e.g. albumina) e molecole a basso-medio peso molecolare, influiscono significativamente sull’efficacia dei trattamenti di dialisi. Alcune tossine di interesse includono p-cresolo, indoxil solfato, β2-microglobuline ed acido urico, ciascuna delle quali gioca un ruolo cruciale nel successo del trattamento di emodialisi e influisce sugli esiti a lungo termine nei pazienti con malattie renali croniche.
L'acido urico è particolarmente importante da rilevare, poiché è riconosciuto come una delle principali tossine uremiche presenti nel dializzato esausto. Esso contribuisce in modo significativo alle misurazioni di assorbimento, ma ha un impatto trascurabile in fluorescenza, rendendo essenziale la progettazione di sensori in grado di rilevarne la presenza tramite tecniche di assorbimento. Al contrario, altre molecole come l'albumina e il p-cresolo, sebbene meno studiate nella letteratura scientifica, forniscono un contributo notevole sia in termini di assorbimento che di fluorescenza. Questi composti assorbono la luce a diverse lunghezze d'onda e sono fondamentali da monitorare poiché potrebbero anche indicare eventuali malfunzionamenti nei filtri dializzanti. Albumina e p-cresolo assorbono ed emettono a diverse lunghezze d’onda, il che permette di isolarne i contributi utilizzando specifici filtri di eccitazione ed emissione. In questo modo, la loro rilevazione può risultare più accurata, migliorando l’affidabilità complessiva del processo di dialisi.
Attualmente, il trattamento emodialitico si basa principalmente sul calcolo di un coefficiente, Kt/V, derivato dalla clearance dell'urea, oltre che su esami del sangue pre- e post-trattamento. L'uso di sensori come quello proposto potrebbe rivoluzionare il processo, consentendo di personalizzare la durata e la modalità del trattamento emodialitico in base ai livelli di tossine rilevati in tempo reale. La possibilità di adattare dinamicamente la dialisi alle esigenze specifiche di ciascun paziente rappresenterebbe un progresso significativo nel miglioramento della terapia. La ricerca si concentra sulla progettazione e sviluppo del sensore precedentemente introdotto che, come già accennato utilizza tecniche di assorbimento e fluorescenza per consentire il monitoraggio continuo di alcune queste tossine, e.g. albumina, p-cresolo, acido urico.
Questo lavoro contribuisce allo sviluppo futuro di sistemi di dialisi personalizzati, abilitando il monitoraggio delle tossine in contesti di assistenza domiciliare. Offrendo informazioni personalizzate sulle specifiche tossine uremiche, apre nuove possibilità per regolare dinamicamente i parametri del trattamento, migliorando la precisione e l’efficacia delle terapie emodialitiche e riducendo le visite ospedaliere.This thesis focuses on the study and development of an optoelectronic sensor for monitoring uremic toxins, with the aim of exploring ways to reduce patient hospitalization in the context of Point of Care (PoC) systems. Hemodialysis, in particular, is a highly debilitating treatment for patients, as it requires multiple sessions per week in a hospital setting, each lasting several hours. Finding a way to apply the PoC approach to such treatments would be highly advantageous, allowing patients to undergo dialysis in a more flexible and personalized manner, reducing the need for frequent hospital visits and improving their quality of life.
Uremic toxins, including protein-bound compounds (e.g., albumin) and low-to-medium molecular weight molecules, significantly affect the effectiveness of dialysis treatments. Some key toxins of interest include p-cresol, indoxyl sulfate, β2-microglobulin, and uric acid, each playing a crucial role in the success of hemodialysis treatment and influencing long-term outcomes in patients with chronic kidney disease.
Uric acid is particularly important to detect, as it is recognized as one of the major uremic toxins present in spent dialysate. It contributes significantly to absorption measurements but has a negligible impact on fluorescence, making it essential to design sensors capable of detecting it through absorption techniques. In contrast, other molecules such as albumin and p-cresol, although less studied in the scientific literature, provide a significant contribution to both absorption and fluorescence. These compounds absorb light at different wavelengths and are essential to monitor as they could also indicate potential malfunctions in dialysis filters. Also, they emit at different wavelengths, which allows their contributions to be isolated using specific excitation and emission filters. This enables more accurate detection, improving the overall reliability of the dialysis process.
Currently, hemodialysis treatment is primarily based on the calculation of a coefficient, Kt/V, derived from urea clearance, as well as pre- and post-treatment blood tests. The use of sensors like the one proposed could revolutionize the process by allowing the personalization of treatment duration and modality based on real-time toxin levels. The ability to dynamically adapt dialysis to the specific needs of each patient would represent a significant advancement in improving therapy.
The research focuses on the design and development of the sensor previously introduced, which, as mentioned, utilizes absorption and fluorescence techniques to enable continuous monitoring of certain toxins, e.g., albumin, p-cresol, and uric acid. This work contributes to the future development of personalized dialysis systems, enabling toxin monitoring in home-care settings. By providing personalized information on specific uremic toxins, it opens new possibilities for dynamically adjusting treatment parameters, improving the precision and effectiveness of hemodialysis therapies, and reducing hospital visits
A simple Maxwellian optical system to investigate the photoreceptors contribution to pupillary light reflex
Full text linkGoing Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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